Electrical selecting or connecting



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3 Sheets-Sheet 2 J. F. T. ENGBLOM Filed Dec. 29, 1951 ELECTRICAL SELECTING OR CONNECTING DEVICE Feb.' 25, 1936.

Feb. 25, 1936. .Y

J.- F. T. ENGBLOM ELECTRICAL SELECTING OR CONNECTING DEVICE Filed Dec. 29, 1931 3 Sheets-Sheet 3 im ev,

Patented Feb. 25, 1936 UNITED STATES ELECTRICAL SELECTING B CONNECTING DEVICE John Fredrik Teodor Engblom, Nottingham, England, assixnor to Ericsson Telephones Limited,

London, England Application December ze, 1931, serial No. 583,120 In Great Britain February 28, 1931 1 Claim.

My invention relates to electric selecting or connecting devices consisting of a plurality of suitably connected relays. Examples of such devices are those known in automatic telephony as 5 relay chains. 'I'he connections of the relay operating coils and contacts are usually such that the relays, or those of them that are required to operate in particular circumstances, operate in a particular order.

lA disadvantage of known arrangements is the presence oi' a large number oi contacts the proper functioning of each of which is essential to the operation of the device as a whole. An object oi my invention is to reduce the number of such contacts.

A My invention relates particularly to devices adapted -to make a non-numerical selection, for example, to connect calling lines in turn to apparatus to which they are to be extended. It

has a special application in a totalizator system in which it is required to make common registering apparatus, or conductors leading thereto, available to a plurality of ticket issuing or like machines.

In my invention I use, in place of a simple series oi' relays, a compound arrangement consisting of two or more groups of relays, each group being similar to (but less in number than) the simple series which the compound arrange- Vment displaces. I apply an operating potential to any one relay, but to not more than one at aI time, by extending the operating potential to one of the groups and thence to a particular relay in that group. To this end, I may provide a chain of serially-related contacts comprising a main portion and a number of branch portions so that the number of serially-related contacts through which the operating potential must pass to reach the most unfavorably situated relay is substantially less than the number of relays. Further, I may perform the actual selection (for example, the connection of a particular ticket issuing machine in a totalizator to common'registering apparatus) according to a combination of relays operated at the same time.

By these means the number of serially-related sections in one group of relays can be reduced to approximately the souare (or higher) root of the number of different selections to be made.

'I'he total number of contacts the failure of which would interrupt the operation of the whole device can therefore be considerably reduced.

The invention canbe applied with advantage to a totalizator system of the kind in which a potential is extended through contacts of relays (Cl. 23S-92) associated with ticket-issuing machines having no bets to be collected to a winding of a relay associated with the next machine having a bet to be collected. Such a system (not embodying the present invention) is shown for explanatory 5 purposes in Figure 3. In this figure; the circuits enclosed Within dotted rectangles are individual to ticket issuing machines and it is assumed that when a particular machine has a bet to be collected, the appropriate relay ST, ST1 STn is l0 operated. Relay BS is common to all the machines and is assumed to be operated whenever betting is in progress. When, for example, relay S'l.'1 is operated, contact stl connects relay A1 to earth via contacts sts and bsi and the wind- 15 ing of relaT CT (in parallel with resistance Ri). The other side of the upper winding of relay A1 is connected to negative battery (not shown) and relay A1 operates to cause the bet to be collected. Contact als extends the earth from contact bs! 20 to succeeding machine circuits (from which it has been temporarily disconnected by contact Stia).

The circuit just described forms part of the system shown in the speciilcation of British Pat- 25 ent No. 368,445 dated January 2nd, 1931, and the speciilcation of the corresponding U. S. Patent No. 2,007,402 dated July 9, 1935, which includes many details not necessary to an understanding 30 of the present invention.

In the application of the present invention to a system of the above-mentioned kind, the machines would be divided into groups, and the relay chain would be employed to extend a potential through contacts associated with groups having no bets to be collected to a chain of contacts associated with the next group having a bet to be collected, and thence through contacts associated with machines in that group having 40 no bets to be collected to a winding of a relay associated with the machine having a bet to be collected. The number of series contacts through which current would have to pass would therefore be considerably reduced and the chance of failure 45 owing to a faulty contact correspondingly decreased.

In order that my invention may be readily understood examples of its application will now be given and reference should be made to the ac- 50 companying drawings, which show modifications of the totalizator system described in the aforementioned British specification.

Figure 1 shows an arrangement that I term a two co-ordinate chainand 55 'Figure 2 one that I term a four co-ordinate chain, both according to my invention.

Figure 3 represents an arrangement forming part of a previous invention described in the specification of British Patent No. 368,445 dated January 2nd, 1931 of which `the present invention is a development or modiilcation` In Figure 3, which represents the portion of the invention described in the prior specification above referred to relevant to the present invention, there is shown as described above a relay chain comprising relay contacts st3, -stl st13, a3, a13 an and relays ST, ST STn and A, A A, 'Ihe chain circuit is completed by a relay CT, resistance Rl, contact bsl and resistance R2. This arrangement constitutes what I may term a single co-ordinate chain, that is, a chain in whichthe location of any ticket issuing machine is completely determined by its distance from one end of the chain. Thus, the machine controlled by relay A is the iirst machine and that controlled by relay Al is the second machine.

Figure 1 of the drawings accompanying the present specification shows the modifications necessary to replace the single co-ordinate chain by a two co-ordinate chain.

As in the case of the earlier specification, the apparatus individual to a ticket-issuing machine includes a relay A, a relay ST, and a relay HO. Relay ST is operated when a key is pressed to send a signal from the machine to common registering equipment. Its object is to start the train of operations which result in the registration of the signal and` the issue of a ticket by the machine, and on this account We will term it a start relay. Relay A is operated when the registering equipment is ready to receive the signal, and its object is to transmit the signal thereto. We will therefore term relay A a signal sending relay. Relay HO, which We will term a hold-oil relay, operates after the signal has been transmitted, and its object is to prevent the re-operation of relay ST for the transmission of further signals by the machine in -question until other machines which may be waiting to transmit signals have had an opportunity of taking the common registering equipment into use. 'I'he circuit arrangements whereby these relays perform their functions are more fully described in -the earlier speciilcation.

In addition to the apparatus individual to each ticket-issuing machine, vthe present drawing shows a relay CT, resistance Rl, contact bsl and resistance R2. These pieces of apparatus also correspond to similarly designated pieces of apparatus in the earlier'case. 'I'he circuit from contact bsl to resistance Rz, however, instead of being completed through contacts st3, st13 stn is normally completed through contacts sal, sbl {snl of relays SA, SB. SN respectively, and only passes through contacts st3, st'3 stn3 after one of said contacts sal, sbl snl has been operated. The operation of any one of these relays is adapted to extend the earth potential from relay CT to a group of ticket issuing machine circuits represented by the dotted rectangles O, 1,-11.. Thus, the operation of relay SA extends the earth potential to the top row of circuits, the operation of relay SB extends it to the second row, and so on. 'Ihere may, of course, be any desired number of rows and any desired number of machines in each row.

In the ticket machine circuits, relays 'such to the similarly designated parts in the previous -invention represented in Figure ,3. Similarly the ticket issuing machine circuit represented by rectangle l incorporates a relay A', and contacts stl, st', al, a'3 and no2, while that represented byv rectangle n incorporates relay A, and contacts such as stnl, stel etc. Each of these series-connected machine circuits corresponds to, and operates in the same way as, a like circuit represented by one of the dotted rectangles shown in Figure 3 described above. Separate relays SA, SB.. SN are provided, one for tential from relay CT to the required group of machines, whence it is extended by the contact such as st3 of the machine having its ST relay operated to the appropriate A relay.

Machines whose contacts st3 are nearer to the operating potential have precedence over machines whose contacts st3 are further away. In addition, groups of machines whose contacts sal, sbl are nearer to the operating potential have precedence over machines whose contacts sbl sul are further away. It is impossible, therefore, for the operating potential to be extended simultaneously to two or more A relays, even though several ST relays and several of relays SA, SB SN may be operated at the same time. There is, moreover, provision for preventing a machine that has been made effective from being made effective again until other waiting machines have had their turn, since the operation of any of relays SA, SB .SN maintains the hold-oil' circuits via contacts ho2 of the machines that have had their turns. This feature does not form part of the present invention and will not therefore be described in detail.

In the modification shown in Figure 2 ofthe accompanying drawings, relay CT, resistance R1, contact bsl and resistance Rn correspond to the similarly designated parts in lFigure 1. Relays SA, SB and SC, contacts sai, sbl and scl, and contacts sa2, sb2 and sc2 correspond to relays SA, SB SN, contacts sal, sbl. sul, and contacts sa2, sb2 sn2 respectively. The machines, however, instead of being l subdivided into groups only once, are subdivided three times. The rst subdivision is into three groups controlled by relays SA, SB and SC and it will be observed that the operation of relay SA, for example, extends the earth potential from relay CT to contacts tal and tbl of relays TA and TB. Similar relays (not shown) are provided for the groups controlled by relays SB and SC. Ac-

cording to whether one, or the other, or neither of tial is further extended to one of three groups' of machines, for example, to the group represented by the top three rectangles in the figure. .The machine of the group which is made eiective depends, as in Figure 1, upon which ST relay is operated,4 the ,circuits individual to the machines being identical with those already described.'

The operation of any ST relay causes the operation of the appropriate relays such as SA, TA

and UA for extending the earth potential to its own group. The arrangement is such that the earth potential cannot be extended to more than one machine at once, even if several relays such as ST, UA, TA and SA are operated at the same time. Since the hold-oi! circuit to contacts no2 is maintained by any of relays SA, SB or SC, a machine is prevented from being made effective twice while another machine that has not had its turn is waiting.

In the arrangement described, there would be one set of contacts sal, sbl and sci, there sets such as those on relays TA and TB, nine sets such as those on relays UA and UB and 27 sets of three machines, that is, eighty-one machines in all. These numbers may, of course, be varied in any suitable manner according to the number of machines to be accommodated and the number of stages of subdivision. An increase in the number of stages of subdivision will generally result in a reduction in the number oi series contacts which must be passed through in order to reach the most unfavourably situated machine.

In Figure 2, instead oi' relays such as SA, TA and UA being operated in series, there may, if desired, be separate contacts such as stl for operating each o! the relays required to extend the earth potential to a particular group of machines.

Although my invention has been described in conJunction with particular circuits I do not limit it thereto, ,and may make considerable modifications in the method o1 carrying it out without departing from its spirit as set out and claimed.

Having now described my invention, what I claim as new and desire to secure by Letters Patent isz- Electrical selecting arrangements in the signalling system of a totalizer comprising a plurality of start relays, a plurality of signal sending relays, and a plurality oi hold-oil relays, corresponding relays in each plurality being associated to form sets of three relays, the said sets oi relays being associated in groups oi sets, a group relay associated with each of the said groups. a circuit for each of the said group relays closed upon the operation of any start relayi in the associated group and opened upon the operation of the corresponding signal .sending relay, means for extending an operating potential to any one of the said signal sending relays, said means comprising a chain of serially related contacts having a trunk portion comprising contacts of the said group relays and branch portions comprising contacts of the said start relays, each of the said group relays having a contact which controls the release of such of the said hold-off relays as are comprised within the corresponding group, so that after the operation of any given signal sending relay and the subsequent operation of the assoelated hold-oi! relay the said hold-oil relay is JOHN FREDRIK TEODOR ENGBLOH. 

